MECHANISM OF GROWTH RATE ENHANCEMENT BY MICROCRYSTALS

摘要

Phenomena of growth rate enhancement (GRE) caused by the presence of newly born micro-crystals such as nuclei were quantitatively analyzed with the system of potash alum-water. Micro-crystals were prepared by mixing stoichiometric amounts of aqueous solutions of aluminum sulphate and potassium sulphate, and were fed as slurry. The size and the number of micro-crystals were controlled by the age after the mixing and the volume of the slurry respectively. After steady growth of a fixed single crystal was confirmed in the supersaturated solution, a known volume of the slurry was added to the solution. The age of the slurry showed a remarkable effect on the growth enhancement in such a way that the younger the age the greater the effect. The extent of the enhancement also increased with the increase of the volume added to the solution. Furthermore the appearances of the crystal surface after the experiments were observed with differential interference microscopy and atomic force microscopy.